The clinical, economic, and patient‐centric burden of insomnia symptom severity in adults with major depressive disorder in the United States

INTRODUCTION: Insomnia is prevalent in adults with major depressive disorder (MDD) and is a key diagnostic criterion of MDD; however, little is understood about the burden of insomnia symptom severity in MDD. We evaluated the relationship between insomnia symptom severity and the clinical, economic, and patient‐centric burden among community‐dwelling individuals with MDD. METHODS: Respondents with diagnosed depression who reported insomnia symptoms in the past 12 months (N = 4402) were identified from the 2019 United States National Health and Wellness Survey. Multivariable analyses assessed the association of Insomnia Severity Index (ISI) with health‐related outcomes while controlling for sociodemographic and health characteristics. Further analyses also controlled for depression severity (9‐item Patient Health Questionnaire). RESULTS: Mean ISI score was 14.3 ± 5.6. Higher ISI was associated with greater depression severity (r = .51, p < .001). After adjustments, a one‐standard deviation (5.6‐point) increase in ISI score was significantly associated with higher depression (rate ratio [RR] = 1.36), anxiety (RR = 1.33) and daytime sleepiness (RR = 1.16) levels, more healthcare provider (RR = 1.13) and emergency room visits (RR = 1.31), hospitalizations (RR = 1.21), work productivity and activity impairment (RRs = 1.27 and 1.23, respectively), and poorer mental and physical health‐related quality of life (β = −3.853 and −1.999, respectively) (p < .001). These findings remained statistically significant when controlling for concurrent depression severity. CONCLUSION: In adults with MDD, greater insomnia symptom severity is associated with worse health‐related outcomes, which suggests the importance of addressing insomnia symptoms as a clinical target for treating MDD.